After a few legal setbacks over the past couple weeks, the most glaring being Judge Lucy Koh’s rejection of Apple’s motion for a preliminary injunction against Samsuing, Apple today was finally on the receiving end of a significant legal decision.

The International Trade Commission (ITC) ruled today that HTC’s Android-based smartphones infringe upon two claims in Apple’s #5,946,647 patent which relates to analyzing and lilnking data structures. Notably, the claim cuts at the heart of Android functionality and does not rest on any HTC initiated enhancements that could easily be tweaked to bypass the patent. Consequently, Apple may be able to successfully apply the patent in question against other Android manufacturers.

Delving deeper into what the patent claim actually covers, Florian Mueller of FOSS Patents explains that it embodies”data tapping.” As an example, you know how you can tap a phone number from within the iPhone Mail client only to be whisked away to the dialer app? Well, that’s one of the implementations at issue here.

What Apple has won is a formal import ban scheduled to commence on April 19, 2012, but relating only to HTC Android phones implementing one of two claims of a “data tapping patent”: a patent on an invention that marks up phone numbers and other types of formatted data in an unstructured document, such as an email, in order to enable users to bring up other programs (such as a dialer app) that process such data. The import ban won’t relate to HTC Android products that don’t implement that feature, or that implement it in ways not covered by those patent claims.

So it looks like Apple’s multitude of legal actions are finally starting to bear some fruit. With an import ban on target for April 19, 2012, HTC’s only hope now is that the ruling gets vetoed by the ITC President, which is apparently not all that common.

The ban will also come with a transition period that will allow HTC to ship infringing devices into the US up until the end of 2013 provided that they’re refurbished models targeted for users seeking warranty replacements.

Mueller concludes

[Apple] now has one patent that it can also assert against other Android device makers unless the data tapping feature can be implemented in non-infringing ways, in which case there wouldn’t even be a point in suing other Android device makers over it. Apple needs to find several more patents of the “data tapping” kind — or, alternatively, one or two fundamental patents for which there’s no viable workaround — in order to really have competitive impact with its many litigations targeting Android. It’s a starting point, and let’s not forget that this is just the first of dozens of lawsuits Apple has already brought against the Android platform.